#include <iostream>
using namespace std;

int q[100]={
5650,4542,3554,473,946,4114,3871,9073,90,4329,
2758,7949,6113,5659,5245,7432,3051,4434,6704,3594,
9937,1173,6866,3397,4759,7557,3070,2287,1453,9899,
1486,5722,3135,1170,4014,5510,5120,729,2880,9019,
2049,698,4582,4346,4427,646,9742,7340,1230,7683,
5693,7015,6887,7381,4172,4341,2909,2027,7355,5649,
6701,6645,1671,5978,2704,9926,295,3125,3878,6785,
2066,4247,4800,1578,6652,4616,1113,6205,3264,2915,
3966,5291,2904,1285,2193,1428,2265,8730,9436,7074,
689,5510,8243,6114,337,4096,8199,7313,3685,211
}; 
int c2=0;
int c5=0;

int main(){
	for(int i=0;i<100;i++){
		int tmp=q[i];
		while((tmp%2)==0){
			c2++;
			tmp/=2;
		}
		tmp=q[i];
		while((tmp%5)==0){
			c5++;
			tmp/=5;
		}
	}
	cout<<min(c2,c5);
	return 0;
} 
